In restaurants, canteens, public service catering facilities and the like, plates, saucers, glasses and cutlery etc., used on the table are washed in dishwashers then dried using drying material and humidity is removed by heating.
In more sophisticated dishwashers this operation is completed by the load being passed through a tunnel where jets of very hot air dry the load through evaporation.
The metal objects, cutlery, saucers etc. are left with traces of limestone, rings and small marks, even where softened water is used and they have to be removed by manually rubbing them with alcohol or vinegar; where the metal is silver or silver plated a tarnish remover is used.